Still Few-Nucleon Systems-After So Many Years

Three- and four-nucleon reactions are discussed. The focus is on the notion of nuclear potentials, on conceptual and technical issues of calculations and on unresolved problems between existing theoretical predictions and experimental data. The special focus is on some historic aspects of the evolution of the field. The views presented have a strong personal bias. Sample results for pd elastic scattering and break-up at low energies and at higher energies are shown. Results for 4N scattering have been obtained so far only for reactions below three-body break-up. They are shown in a figure for elastic p3He scattering and for the reactions dd → p3H and dd → n3He , related by charge symmetry; The total elastic n-3H cross section is shown. (author)